McXtrace - Monte Carlo Xray Tracing, is a joint venture by

Our code is based on technology from

Code repository (shared with 'McStas') is located at github.com/mccode-dev

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• To download the latest release: download area
• For installation instructions :
• McXtrace 3.x installation
• For a quick list of the available commands: commands

Recent McXtrace News

Migrating from McXtrace 1.x to 3.x? - Use the wiki-based guides

January 7th, 2026: McStas and McXtrace 3.6.5 released

What's Changed - Main Changes:

Bugfixes, new features, all common to McStas and McXtrace:

• macOS bundles in 3.6.1 did not actually install that version but something earlier. Fixed by pinning in yml file, @willend in #2285
• PDF manuals had wrong version numbers, @willend in #2285
• Allow mcrun / mcdisplay to run / visualize without access to .c/.instr by @willend in #2281
• mcgui/mxgui editable font colors, handle long filenames without extreme window resizing by @willend in #2275
• Fix cross-platform sort-order issue in PowderN by @willend in #2272
• Platform-independent reflection list sort in Single_crystal by @willend in #2273
• mcrun/mxrun: feature addition - scan by seed by @willend in #2276
• Add mcplot toggle to "plot 1D-curves from 0-value" in linear mode by @willend in #2278
• Add commentstring to vim editor by @Lomholy in #2284

Other stuff

• %Example adjustments, McXtrace by @willend in #2269
• Test_SANS/Test_SAXS, supplement stats by x10 SPLIT by @willend in #2270
• Use ${{ matrix.mpi }} to ensure different output dirs by @willend in #2271
• Fix indentation bug - issue #2279 by @willend in #2280
• Temporarily disable this instr from McXtrace tests by @willend in #2283

Full Changelog:https://github.com/mccode-dev/McCode/compare/v3.6.1...v3.6.5